Methods and apparatus for electrode placement and tracking

ABSTRACT

An electrode carrier system includes one or more electrode assemblies having an electrode body. One or more tubular members extend from the electrode body and define a lumen terminating in a distal opening. The electrode assemblies carry a reservoir containing a conductive fluid or gel. The reservoir is in fluid communication with the lumens in the tubular members, and the electrode assemblies are typically supported on a backing which may optionally be configured as a headband. Systems are for tracking patient movement may be used in combination with the electrode carrier system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/783,346, filed Oct. 13, 2017, now U.S. Pat. No. ______; which is acontinuation of U.S. patent application Ser. No. 15/387,381, filed Dec.21, 2016, now U.S. Pat. No. 9,820,670; which claims the benefit ofprovisional application 62/314,873, filed on Mar. 29, 2016; the fulldisclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to methods and apparatus for facilitatingthe placement of one or more electrodes against the skin surface of apatient and monitoring a patient status. More particularly, the presentinvention relates to methods and apparatus for facilitating the speedand efficiency for placing one or more electroencephalogram (EEG)electrodes against a patient's the scalp, optionally in combination withtracking the movements of a patient.

Electrodes typically used in electrocardiography andelectroencephalography generally provide for uniform contact between themetal electrode and the skin to prevent electrical noise due to theinterface between the electrode and skin surface. To provide for uniformcontact with the skin area, a conductive gel may be applied to the skinsurface to facilitate electrical conduction with the electrode. However,when electrodes are to be placed at multiple locations over thepatient's scalp, the application of the gel in combination withdetermining electrode placement not only requires specialized trainingand skill but is also very time consuming.

Some electrodes utilize conductive gel interfaces which are pre-formedfor contacting the electrode but the gel interfaces become ineffectivewhen hair is present and may sometimes require the removal of theunderlying hair.

It has been suggested the EEG electrodes may be formed with an on-boardconductive gel dispenser for delivering the gel immediately after aplacing a headgear on a patient. See, U.S. Pat. No. 6,640,122. Thedevices of the '122 patent, however, do not provide for preserving thegel as a component of the electrode for extended time periods.

Accordingly, there exists a need for methods and devices whichfacilitate the speed of placing electrodes and also for facilitatingcontact between the electrode and the skin surface even in the presenceof hair without requiring manually prepare the hair and scalp for eachelectrode contact. It would be particularly desirable if such methodsand devices could provide for incorporation of a conductive fluid or gelas part of the electrode assembly as well as for preserving suchconductive fluids or gels for extended time periods. At least some ofthese needs will be met by the inventions described and claimed herein.

2. Description of the Background Art

EEG electrodes having plungers and/or capsules for dispensing conductivegels are described in U.S. Pat. Nos. 9,408,575; 8,805,470; 6,640,122 andU.S. Patent Publication No. 2007/0255127. U.S. Pat. No. 6,381,481describes an EEG electrode with fingers for spreading hair. Otherpatents of interest include U.S. Pat. Nos. 7,841,301; 4,709,702;5,273,037; and 5,357,957; 4,166,457; 4,079,731; 4,033,334; 3,830,229;and U.S. Patent Publication No. 2007/0272313. Headgear includingintegrated EEG electrodes are available commercially from Advanced Brainmonitoring, Inc., Carlsbad, Calif., under the tradename B-Alert® MobileEEG (http://www.advancedbrainmonitoring.com) and from Hydrodot, Inc.,Westford, Mass., under the tradename StatNet™ EEG headpiece(http://www.hydrodot.net).

SUMMARY OF THE INVENTION

Generally, in facilitating the placement and contact of electrodes uponthe selected areas of the skin surface, an electrode carrier system maygenerally comprise an electrode body which is at least partiallyelectrically conductive, one or more tubular members extending from theelectrode body, each of the one or more tubular members defining a lumentherethrough and a distal opening, a reservoir having a compressiblestructure and containing a conductive fluid or gel which is in fluidcommunication with the one or more tubular members, and a backingsupporting the electrode body and reservoir.

In other variations, the electrode carrier system may generally comprisean electrode body having one or more tubular members extendingtherefrom, each of the tubular members defining a lumen therethrough anda distal opening, a reservoir having a compressible structure whichdefines an internal volume and which is in fluid communication with theone or more tubular members, and a controller and/or output device whichis in electrical communication with the electrode body, wherein thecontroller and/or output device is configured to receive electricalsignals from the electrode assembly and record and/or output acorresponding response.

The electrode carrier system may generally comprise a backing securedaround the head of a patient. The backing may be configured as aheadband although the carrier system may be incorporated into any numberof other platforms or positioning mechanisms for maintaining theelectrodes against the patient body. The individual electrodes arespaced apart from one another so that when the headband is positionedupon the patient's head, the electrodes are aligned optimally upon thehead for receiving EEG signals. The carrier system may have each of theelectrodes electrically coupled via corresponding conductive wiresextending from the backing and coupled, e.g., to a controller and/oroutput device. Although in other variations, the electrodes may becoupled to the controller and/or output device wirelessly.

The controller and/or output device may generally comprise any number ofdevices for receiving the electrical signals such aselectrophysiological monitoring devices and may also be used incombination with any number of brain imaging devices, e.g., fMRI, PET,NIRS, etc.

The electrodes, as described herein, may be positioned upon the backingto quickly enable conductive contact with the underlying skin whileallowing for patient comfort such as when the patient is reclined withthe back or side of their head resting upon a surface without discomfortfrom the electrodes.

In one variation of the electrode carrier system, each of the electrodesmay be configured to include a visual or haptic indicator to providefeedback to the user that sufficient electrode connection with the skinsurface has been achieved. For instance, each electrode may incorporatean impedance sensor and indicator such that when the controller and/oroutput device detects a relatively low impedance, e.g., 5-50 kΩ, in aparticular electrode, that electrode may have its indicator (such as anLED) actuated to indicate that sufficient electrical contact between theelectrode and underlying skin is achieved.

Turning now to the electrode configurations, one variation of anelectrode carrier system may comprise each of the electrodes enclosedwithin a reservoir which is pre-filled with a conductive gel or fluid.Each electrode may be configured into a flattened or atraumaticconfiguration which is contained within a respective reservoir and eachreservoir may be formed of any number of flexible materials, e.g.,silicone, polyurethane, rubber, etc., which can readily collapse. Theelectrodes may be coupled via conductive wires passing through a lumendefined through the backing separated from the electrodes by asubstrate. Each reservoir may also respectively define one or moreopenings through which the conductive gel or fluid may be expelled.

Once the platform has been situated over the patients' head, the usermay press upon each of the reservoirs such that the conductive fluid orgel flows through the openings and onto the skin of the patient. Theconductive fluid or gel expelled through the openings may maintain fluidcommunication between the skin surface and the respective electrodessuch that the detected electrical signals may be transmitted from theskin and to the electrodes. Moreover, because of the flexibility of thereservoirs, once the conductive fluid or gel has been expelled intocontact with the skin surface, the backing may lie flat against the skinsurface so that the patient may comfortably lay their head upon asurface while still maintaining electrical contact with the electrodes.

Another electrode variation may be comprised of one or more loops ofconductive wire or ribbon which are able to readily bend or flex againstthe skin surface. The electrode carrier system may include a pressurerelease reservoir for containing the conductive fluid or gel, asdescribed above, around each of the electrodes so that the conductivefluid or gel may be expelled around and within the one or more loops toensure a conductive path.

Another variation may be configured into one or more tubular memberswhich extend from the backing transversely. The tubular members may beeach arranged in a circular pattern for each electrode and they may alsodefine a lumen therethrough with an opening defined at each distal end.Each of the tubular members may be fabricated from a conductive metalwhich may retain its tubular shape when in use or which may besufficiently thin and flexible to bend or yield when placed against thepatient's skin surface. Alternatively, the tubular members may befabricated from a flexible material which is coated or layered with aconductive material such that the members retain their flexibility. Ineither case, the conductive fluid or gel may be either contained withinthe tubular members or they may be retained within a pressure releasereservoir, as described above, surrounding or in proximity to eachelectrode. Because the tubular shape of the electrodes, they may readilypass through the patient's hair, if present, and into contact againstthe skin surface while maintaining electrical contact.

Yet another variation of an electrode embodiment may also utilize apressure release reservoir filled with the conductive fluid or gel. Thereservoir may be formed of a flexible material, e.g., silicone,polyurethane, rubber, etc., extending from the backing to form a curvedor arcuate structure with one or more openings defined over thereservoir. These openings may remain in a closed state until a force isapplied to the reservoir and/or backing which may urge the fluid or gelcontained within to escape through the openings and into contact withthe outer surface of the reservoir and underlying skin surface. Theouter surface of the reservoir may have a layer of conductive materialin electrical contact with the conductive wires so that once the fluidor gel has been expelled from within the reservoir and out onto theconductive material upon the reservoir outer surface and skin surface,electrical contact may be achieved.

In yet another variation, an electrode carrier system having anelectrode body may define one or more tubular members extending from thebody such that the members project transversely away from the backing.The electrode body may be comprised of a conductive material such as ametal which may be rigid. However, in other variations, the body may befabricated from a conductive material which is also flexible, e.g.,conductive silicone, and/or from a flexible material, e.g., silicone,polyurethane, rubber, etc., which may be coated or layered with aconductive material such that the underlying tubular members retaintheir flexibility.

In either case, the body may be secured to the backing such that the oneor more openings are defined along the body and extending through themembers are in fluid communication with a reservoir having acompressible housing. The reservoir may also be secured to the backingand contain a volume of conductive fluid or gel local to the electrodebody. The tubular members may be arranged in a uniform pattern or in anarbitrary pattern as well and while the members are shown arranged in acircular configuration, other patterns may be implemented. When thebacking has been secured to the patient, the reservoir may be pressed orurged such that the fluid or gel contained within is expelled througheach of the tubular members and into contact against the underlying skinsurface through corresponding distal openings. The elongate nature ofthe members may enable them to pass readily through the patient's hair,if present, and into direct contact against the skin surface.

In another variation, an electrode carrier system having a tubular bodymay define one or more openings over its surface. The tubular body mayhave one or more tubular members which extend in a spiral or helicalpattern away from the backing. The tubular members may define a lumentherethrough which extends from the tubular body and to a distal openingat its tip. The backing may further define a reservoir which contains avolume of conductive fluid or gel such that the body is in fluidcommunication with the reservoir. Additionally and/or alternatively, thedistal tips of the members may present a roughened surface forcontacting the skin. The optionally roughened tips may be rotated orotherwise translated or moved across over the skin surface by the userto at least partially exfoliate the skin surface to facilitateelectrical contact.

In particular, a distal skin-contacting surface of the electrodeassembly may be modified to prepare the skin surface to enhanceelectrical conductance (.i.e. lower electrical resistance) between anelectrically conductive portion of the electrode assembly and the skinwhen that electrically conductive portion is in physical contact withthe skin. For example, the tissue-contacting surface(s) of the electrodeassembly may be modified to have an abrasive surface, e.g. by coatingwith abrasive particulate; may be formed or molded to have protrudingrigid features, e.g. bumps, ridges, or the like; and/or may be coatedwith a material that lowers the electrode connection impedance. Suchsweeping and/or chemical coating of the tissue-contacting surface(s) ofthe electrode assembly over the target tissue location could scrub,dissolve and/or otherwise disrupt dead tissue and break-up scalp oil. Inspecific examples, at least a portions of a distal tissue-contactingsurface of the electrode assembly, for example the distal surface(s) ofat least some of the tubular members, comprise such surface features,surface coatings, surface treatments, or combination thereof to improvethe quality of the electrode connection.

In yet another variation, the electrode carrier system may also beutilized for other applications such as patient motion trackingemploying either visual motion tracking or accelerometers. The motiontracking may be coupled with an EEG device to reject EEG data duringheavy movements. The visual motion tracking allows the camera toautomatically track the patient with the headband and offers recordingprecision as well as more mobility to patients.

In another specific aspect of the present invention, an electrodeassembly comprises an electrode body and one or more tubular membersextending from the electrode body, typically from a bottom surface ofthe electrode body. Each tubular member has a distal tip, and at leastsome of the tubular members have a lumen with a distal opening in thedistal tip. A reservoir containing a conductive fluid or gel isoptionally disposed in the electrode body, and the electrode body isconfigured for dispensing the conductive fluid or gel from the reservoirthrough the lumen(s) and out of the distal opening(s) of the tubularmember(s). Alternatively, in some embodiments, the conductive fluid orgel may be dispended onto or through the lumens of the tubular memberusing a syringe or other separate delivery device.

As used herein, the term “conductive” will mean electrically conductive,i.e. having a very low electrical resistance and the ability to carrylow current biological signals such as EEG signals.

As further used herein, the phrase “tubular member” will mean agenerally elongated structure, i.e. having a length extending away fromthe bottom of the electrode body greater than its width parallel to thebottom of the electrode body, where the width is measured at itsnarrowest point. Usually, the length will be at least twice the width,frequently being at least three times the width. Exemplary tubularmembers may have generally circular horizontal peripheries (in a planeparallel to the bottom of the electrode body) making them generallycylindrical along a vertical axis. Other exemplary tubular members mayhave crescent-shaped horizontal peripheries.

In specific embodiments, the electrode assembly will typically compriseat least two tubular members, and may comprise three tubular members,four tubular members, or even more. The tubular members will usuallydepend vertically downwardly from a bottom surface of the electrode bodyand will be specifically configured so that they may penetrate apatient's hair so that a distal tip of the tubular members will be ableto engage and provide reliable electrical contact with a patient'sscalp. The tissue engagement areas of the tubular members on bottomsurface of the electrode body will usually be 50% or less of the area ofthe bottom surface, frequently being 30% or less of the area of theelectrode body, and usually being at least 5% of the area of the bottomsurface. Thus, the tissue engagement areas of the tubular members onbottom surface of the electrode body will usually be in a range from 5%to 50% of the area of the bottom surface, typically being in a rangefrom 5% to 30% of the area of the bottom surface.

In most instances, the tubular members will extend from a generallyplanar bottom of the electrode body at a perpendicular angle. In otherinstances, however, the tubular members may extend at an angle anywherein the range from 30° to 150° relative to the plane, typically beingfrom 60° to 120° relative to the plane. In other instances, however, thetubular members may have other configurations, for example beingconfigured in a helical shape so that they may penetrate hair to apatient's scalp by rotating the electrode assembly around a verticalaxis.

In other specific embodiments of the present invention, the distal tipsof at least some of the tubular members will have a skin preparation,e.g. tissue-roughening, surface. For example, the tissue-rougheningsurface may comprise an abrasive material, such as a grit or otherabrasive particles, formed over at least a portion of the distal tip ofthe tubular member. In other instances, the surface-roughening maycomprise surface features, such as ridges, bumps, grooves, and the like,formed over at least a portion of the distal tip which contacts thepatient's skin.

The electrode body, and in particular the tubular members connected tothe electrode body, may be formed at least partly from electricallyconductive materials, such as metals, electrically conductive coatings,embedded wires, or electrically conductive polymers. In such instances,the electrode body and/or the tubular members will provide at least aportion of the electrical path needed to conduct biological currentsfrom the tip of the tubular member(s) to an electrical terminal or otherconductive connector on the electrode body as described below. In otherinstances, however, the electrode body and/or the tubular members may beformed primarily or even entirely from an electrically non-conductivematerial. In such instances, the electrically conductive fluid or gelwill provide most or all of the electrically conductive path needed todeliver the biological current from the distal tip of the tubular memberto the electrical terminal after such conductive fluid or gel has beendistributed throughout the electrode body and tubular member, asdescribed in greater detail below.

The tubular members may comprise a variety of geometries. Often, thetubular members will be generally cylindrical having a lumen extendingtherethrough. In other instances, however, the tubular members may beformed as “prongs” having a relatively broad tissue-contacting regionalong a curved “axis” at their distal tips. In many instances, thetissue-contacting regions of the prongs will be generallycrescent-shaped so that they will follow a generally circular path asthey are rotated against the patient's tissue, as described in moredetail below.

The prongs and other tubular members of the present invention willpreferably have a port in their tissue-contacting surfaces fordelivering the electrically conductive fluid or gel to the patient'sskin. In some instances, ports may be formed in a generally flat bottomsurface of the tubular members or prongs. In other instances, the portsmay be connected to a channel or other distribution feature on thetissue-contacting surface of the prong or other tubular member. In stillfurther specific embodiments, the ports for delivering the electricallyconductive fluid or gel may be located in a recessed surface of theprong which may adjacent to a tissue-contacting lower surface of theprong or other tubular member.

While the electrode assemblies will usually comprise one or more tubularmembers as just discussed, in some alternative embodiments, theelectrode body may have a generally flat bottom free from tubular andother protruding members. The flat bottom will be configured to engagethe skin and have openings to release a conductive fluid or gel in anyof the ways described elsewhere herein for delivering the conductivefluid or gel through a tubular member. The tissue-contacting surface(s)of such flat bottoms may be modified in any of the ways discussed hereinto have electrical conductivity with the target tissue surface(s).

The reservoir in the electrode body which contains the conductive fluidor gel will preferably be sealed to preserve the fluid or gel and allowthe long-term storage of an electrode assembly which has been pre-filledwith the electrically conductive fluid or gel. In specific embodiments,the reservoir will have a sealed dispensing container within thereservoir which may be incorporated into the electrode assembly duringthe initial manufacture thereof. For example, the sealed dispensingcontainer may comprise a sealed dispensing container, e.g. a packet,which is constrained within a chamber in the electrode body, where theelectrode body comprises a plunger configured to be manually pressedagainst the sealed dispensing container to deliver the electricallyconductive fluid or gel from the sealed dispensing container through thelumen(s) and out of the distal opening(s) of the tubular member(s). Inspecific instances, the sealed dispensing container and the plunger willbe located in an upper portion of the electrode body, and the tubularmember(s) will extend from a lower surface of the electrode body. Insuch specific instances, the electrode body will be configured to definea flow path to deliver the conductive fluid or gel from the sealeddispensing container through the lumen(s) in the tubular member(s) andout of the distal opening(s) of the tubular member(s).

The electrode assemblies of the present invention may be provided withvarious mechanisms for releasing the electrically conductive fluid orgel from such a sealed dispensing container. For example, the reservoirmay have a dispensing hole which is configured to define a ruptureregion on the sealed dispensing container when the sealed dispensingcontainer is pressurized by the plunger. In other instances, however,the sealed dispensing container may comprise any one of a syringe, amanual squeeze tube, a roller squeeze tube, or the like, which areincorporated into or otherwise combined with the electrode body.

The electrode assemblies of the present invention will typically have anelectrically conductive terminal mounted on the electrode body andconfigured to allow attachment of the electrode assembly to a controlleror other instrumentation for measuring the EEG or other electricalbiological signals. The electrically conductive terminal will beconfigured to electrical couple to wires or other conventionalelectrical conductors to provide a connection to the control system. Inthe disclosed embodiments, the electrically conductive terminal willhave an interior portion which is located in and exposed to the flowpath within the electrode body for the electrically conducted fluid orgel. In some instances, the electrically conductive terminal will be theonly solid electrically conductive component which is part of theelectrode assembly. The electrical conduction of the biological signalto the electrically conductive terminal may be provided entirely by theelectrically conductive fluid or gel after such fluid or gen has beendistributed throughout the electrode body. In other instances, however,additional electrically conductive components, coatings, wires, or thelike, may be provided within the electrode body of the electrodeassembly in order to provide or enhance electrical conductivity.

In further aspects of the present invention, an electrode carrier systemcomprises an elongated backing, typically figured as a headband orheadgear for placement upon a patient's head. A plurality of electrodeassemblies, as described above, are mounted on and distributed over alength of the elongated backing, and at least one electricallyconductive wire or other conductor is connected to each of the electrodeassemblies to deliver low current biological signals from the electrodeassemblies to a separate controller and/or output device.

The systems of the present invention may further comprise the controllerand/or output device configured to receive the low current biologicalsignal from the electrode assemblies. Additionally, the controller maybe configured to output a response corresponding to the electricalsignals from the electrode assemblies. In preferred embodiments, thedistal tips of at least some of the tubular members will define atissue-roughening or other skin preparation surface and at least some ofthe electrode assemblies will be movably, e.g. rotatably, mounted on theelongated backing to allow a user to sweep or scrub the tissue-engagingsurfaces of the assemblies over target tissue surface(s) to a abrade thetissue surface to enhance electrical contact. In particular, theelectrode assemblies may be rotated or alternatively translated (pushedback-and-forth) over the contacting tissue surface after the elongatedbacking of the electrode carrier system has been mounted on thepatient's head.

In a further specific aspect of the present invention, a plurality ofelectrodes may be placed on patient's scalp by placing a headband orother headgear around the patient's scalp. The headband carries aplurality of electrode assemblies, for example as described above, anddistal tip(s) of one or more tubular members extending from at leastsome of the electrode assemblies are engaged against scalp tissue. Anelectrically conductive fluid or gel is then extruded from a reservoirdisposed in at least some of the electrode assemblies so that the fluidor gel passes through the tubular members to form an electricallyconductive path to the patient's scalp tissue. The plurality ofelectrode assemblies are connected to a controller and/or output deviceconfigured to receive low power biological current from the electrodeassemblies. In the specific aspects of the methods of the presentinvention, the distal tips of at least some of the tubular members willbe positioned through hair on the patient's scalp. At least some of theplurality of electrode assemblies may be rotated in order to abradescalp tissue adjacent the distal tip(s) of said one or more tubularmembers in order to lower contact resistance between the electrodeassembly and the scalp tissue. Usually, at least some of the tubularmembers define the skin preparation, e.g. tissue-roughening surface, andthe electrically conductive fluid or gel is extruded from the reservoirthrough the lumens into the tubular members and out the distalopening(s) on the distal tips of the tubular member(s) onto the scalptissue. In specific instances, the electrically conductive fluid or gelmay be extruded out of or through grooves on the distal tips of thetubular members. Such extrusion typically comprises manually applyingexternal pressure to a sealed dispensing container which holds theelectrically conductive fluid or gel, or the sealed dispensing containeris incorporated into the electrode assembly, typically being disposed ina chamber within a electrode body. In specific instances, applyingexternal pressure to the sealed dispending containers may comprisepressing a plunger to engage a rupturable sealed dispensing containerthat carries the electrically conductive fluid or gel. Alternatively,applying external pressure to the sealed dispensing container maycomprise manually squeezing a tube, manually depressing a syringeplunger, rolling a squeezed tube, or the like. In many instances, theelectrically conductive path to the patient's scalp tissue is formedsolely by the conductive fluid or gel. In other instances, however, theelectrically conducted path to the patient's scalp may be formed atleast party by an electrically conductive structure on the tubularmember or elsewhere within the electrode assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of a patient with an electrode carriersystem configured as a headband.

FIG. 2 illustrates a perspective view of one variation of the electrodecarrier system where individual electrodes may be configured to indicatewhether adequate contact is made with the underlying skin surface.

FIG. 3 illustrates a detail cross-sectional side view of anothervariation of the electrode carrier system where each of the electrodesmay be encased or surrounded by a pressure release reservoir.

FIG. 4 illustrates a detail cross-sectional side view of anothervariation where the electrodes may be formed by one or more loops ofconductive wire or ribbons.

FIG. 5 illustrates a detail cross-sectional side view of anothervariation where each of the electrodes may be formed by one or moreconductive tubes which define conduits.

FIGS. 6A to 6C illustrate cross-sectional side views of yet anothervariation where each electrode may include a compressible reservoirhaving one or more openings.

FIGS. 7A and 7B illustrate top and partial cross-sectional perspectiveviews of another variation where each electrode is formed to have one ormore conductive tubes in fluid communication with a compressiblereservoir.

FIG. 8 illustrates a partial cross-sectional side view of anothervariation where each electrode is configured into a helicalconfiguration which may be rotated relative to the supporting platform.

FIG. 9 illustrates an example of optically tracking the movement of apatient in combination with the electrode carrier system.

FIG. 10 illustrates another example of utilizing one or moreaccelerometers for detecting the patient's movements in combination withthe electrode carrier system.

FIG. 11 illustrates an electrode carrier system of the present inventioncomprising a headband having a plurality of electrode assembliesdistributed over a length thereof.

FIG. 12 illustrates an exemplary electrode assembly constructed inaccordance with the principles of the present invention.

FIG. 13 illustrates the electrode assembly of FIG. 12 shown in anexploded view.

FIG. 14 illustrates the electrode assembly of FIG. 12 shown in across-sectional view.

FIG. 15 shows a cross-sectional view of a lower portion of the electrodeassembly of FIGS. 12-14 taken along line 15-15 of FIG. 14.

FIG. 16 is simplified illustration of the electrically conducted fluidor gel flow path within the electrode assembly of FIGS. 12-15 where thespecific components and flow path segments use the numbering employed inFIGS. 12-15.

FIGS. 17 and 18 are detailed views of a bottom portion of the electrodeassembly of FIGS. 12-15.

FIGS. 19 and 20 illustrate an alternative bottom portion which could besubstituted for the bottom portion illustrated in FIGS. 12-15.

FIGS. 21-27 each illustrate a further alternative configuration of abottom portion of an electrode assembly constructed in accordance withthe principles of the present invention.

FIGS. 28A-28C illustrate yet another alternative configuration of abottom portion of an electrode assembly having a flat surface which isfree from tubular members and other similar structures.

FIGS. 29A-29C illustrate a further exemplary electrode assemblyconstructed in accordance with the principles of the present inventionhaving one or two grommets for attachment of the electrode assembly to aheadband and further having a vertical passage for introducing anelectrode gel using an assembly or other delivery device.

FIGS. 30A-30C illustrate yet another exemplary embodiment of anelectrode assembly having a single, cylindrical tubular member on abottom surface of a lower portion thereof and received within a buckleassembly to allow rotation when the buckle is attached to a headband.

FIGS. 31A and 31B illustrates a still further exemplary embodiment of anelectrode assembly constructed in accordance with the principles of thepresent invention where the electrode assembly is configured to axiallytranslate within a slot of a buckle assembly.

DETAILED DESCRIPTION OF THE INVENTION

The electrode carrier system 10 may generally comprise a backing 12shown in the side view of FIG. 1 which illustrates the carrier system 10secured around the head H of patient P. The backing 12 is shownconfigured as a headband in this variation although the carrier system10 may be incorporated into any number of other platforms or positioningmechanisms for maintaining the electrodes against the patient body. Thebacking 12 is shown configured as a headband in this variation and theindividual electrode assemblies 14 are spaced apart from one another sothat when the headband is positioned upon the patient's head H, theelectrode assemblies 14 are aligned optimally upon the head H forreceiving EEG signals. The electrode carrier system 10 may have each ofthe electrodes assemblies 14 electrically coupled via correspondingconductive wires 16 extending from the backing 12 and coupled, e.g., toa controller and/or output device 18. Although in other variations, theelectrodes assemblies 14 may be coupled to the controller and/or outputdevice 18 wirelessly.

The controller and/or output device 18 may generally comprise any numberof devices for receiving the electrical signals such aselectrophysiological monitoring devices and may also be used incombination with any number of brain imaging devices, e.g., Mill, PET,NIRS, etc. In one particular variation, the electrode embodimentsdescribed herein may be used in combination with devices such as thosewhich are configured to receive electrical signals from the electrodesand process them.

The electrodes assemblies A4, as described herein, may be positionedupon the backing 12 to quickly enable conductive contact with theunderlying skin while allowing for patient comfort such as when thepatient P is reclined, as shown, with the back or side of their head Hresting upon a surface without discomfort from the electrodes 14.

One challenge in ensuring that the individual electrodes 14 makesufficient contact with the underlying skin is the presence of hair HRon the scalp S of the patient P. Prior to the present invention, theregion where the electrodes assemblies 14 are placed upon the scalp Swere typically shaved to remove excess hair (if present) whichinterferes and inhibits electrical contact between the electrodeassemblies 14 and the scalp surface. In contrast, the electrode carrierassemblies of the present invention as described herein enable rapidreliable electrical contact on individual electrode assemblies throughthe hair HR and with scalp surface without having to remove the hair.

In one variation of the electrode carrier system 10, FIG. 2 illustratesa perspective view where each of the electrodes 14 may be configured toinclude a visual or haptic indicator to provide feedback to the userthat sufficient electrode connection with the skin surface has beenachieved. For instance, each electrode 14 may incorporate an impedancesensor and indicator such that when the controller and/or output device18 detects a relatively low impedance, e.g., 5 kΩ, in a particularelectrode 14, that electrode may be actuated to indicate that sufficientelectrical contact between the electrode 14 and underlying skin isachieved.

FIG. 2 shows an example where each of the electrodes 14 may alsoincorporate visual indicators such as one or more light emitting diodes(LEDs). When sufficient electrical contact is achieved, the LED on aparticular electrode 14 may emit a light of a first color 20, e.g.,green, but if an electrode 14 has not achieved sufficient electricalcontact, it may emit a light of a second color 22, e.g., red.Alternatively, a single color LED may be used where sufficient contactmay be indicated by steady illumination of the LED and insufficientcontact may be indicated by a blinking LED. In other variations, anelectrode may include, e.g., a piezoelectric transducer, eccentricallyloaded weight coupled to a motor, etc., to provide for a vibration orother haptic response to indicate whether the electrode 14 hassufficient electrical contact with the underlying skin. In this manner,the electrodes 14 may efficiently provide direct indication ofelectrical contact rather than having to review a separate controller orindicator.

Turning now to the electrode configurations, FIG. 3 illustrates across-sectional detail side view of one variation of an electrodecarrier system 35 where the electrodes 32A and 32B may be enclosedwithin a reservoir which is pre-filled with a conductive gel or fluid.Each electrode 38A, 38B may be configured into a flattened or atraumaticconfiguration which is contained within a respective reservoir 30A, 30Band each reservoir 30A, 30B may be formed of any number of flexiblematerials, e.g., silicone, polyurethane, rubber, etc., which can readilycollapse. The electrodes 38A, 38B may be coupled via conductive wires 16passing through a lumen 34 defined through the backing 12 separated fromthe electrodes by a substrate 36. Each reservoir 30A, 30B may alsorespectively define one or more openings 32A, 32B through which theconductive gel or fluid may be expelled.

Once the platform 12 has been situated over the patient's head H, theuser may press upon each of the reservoirs 30A, 30B such that theconductive fluid or gel 40A, 40B flows through the openings 32A, 32B andonto the skin of the patient P. The conductive fluid or gel 40A, 40Bexpelled through the openings may maintain fluid communication betweenthe skin surface and the respective electrodes 38A, 38B such that thedetected electrical signals may be transmitted from the skin and to theelectrodes 38A, 38B. Moreover, because of the flexibility of thereservoirs 30A, 30B, once the conductive fluid or gel 40A, 40B has beenexpelled into contact with the skin surface, the backing 12 may lie flatagainst the skin surface so that the patient P may comfortably lay theirhead upon a surface while still maintaining electrical contact with theelectrodes 38A, 38B.

FIG. 4 shows a side view of another electrode carrier system 35 where apair electrode assemblies 50A, 50B may include one or more loops ofconductive wire or ribbon 51A, 51B which are able to readily bend orflex against a skin surface. Some or all of the electrode assemblies50A, 50B may include a pressure release reservoir (shown in broken lines53A and 53B) for containing a conductive fluid or gel 52A, 52B, asdescribed above, around each of the wire or ribbon electrodes 51A, 51Bso that the conductive fluid or gel 52A, 52B may be expelled around andwithin the one or more loops to ensure a conductive path between theloops and the scalp. Alternatively, rather than using the pressurerelease reservoir, an amount of conductive fluid or gel may be simplyplaced upon the electrode assemblies 50A, 50B prior to placement againstthe patient's skin surface. Each of the wire or ribbon electrodes 51A,51B may be electrically connected via conductive wires 16, and becausethe wire or ribbon electrodes 51A, 51B will preferably have a thindiameter or width, they may easily pass through the patient's hair andinto contact with the scalp surface even when they bend or flex.

FIG. 5 shows a side view of another variation of an electrode carriersystem 56 having a plurality of electrode assemblies 58A and 58B each ofwhich may include one or more tubular members 60A, 60B which may extendperpendicularly or at an angle from an inner surface (the surface thatcontacts the patient's scalp) of the backing 12. The tubular members60A, 60B may define a lumen therethrough with an opening 62A, 62Bdefined at each distal end. Each of the tubular members 60A, 60B may befabricated from a conductive metal which may retain its tubular shapewhen in use or which may be sufficiently thin and flexible to bend oryield when placed against the patient's skin surface. Alternatively, thetubular members 60A, 60B may be fabricated from a flexible materialwhich is coated or layered with a conductive material such that themembers retain their flexibility. In either case, a conductive fluid orgel 64A, 64B may be either contained within the tubular members 60A, 60Bor they may be retained within a pressure release reservoir, asdescribed above but not shown in FIG. 5, surrounding or in proximity toeach electrode. Because the tubular shape of the electrodes, they mayreadily pass through the patient's hair, if present, and into contactagainst the skin surface while maintaining electrical contact. Thetubular members 60A, 60B may be arranged in tandem pairs, as shown, ormay be arranged in a triangular, rectangular or circular pattern whenthere are three, four, or more tubular members in a single electrodeassembly 58A, 58B.

Referring to FIGS. 6A-6C, a further embodiment of an electrode carriersystem 68 includes a pressure release reservoir 70 filled with aconductive fluid or gel 74. The reservoir 70 may be formed of a flexiblematerial, e.g., silicone, polyurethane, rubber, etc., and extends from abacking 12 to form a curved or arcuate structure with one or moreopenings 72 defined over an interior of the reservoir 70. These openings72 typically remain in a closed state until a force F is applied to thereservoir 70 and/or backing 12 to cause an electrically conductive fluidor gel 74 contained within the interior of the reservoir to escapethrough the openings 72, as shown in FIG. 6B, and into contact with anouter surface of the reservoir 70 and form an electrically conductivepath to underlying skin surface. A layer of conductive material 76 iselectrically coupled to conductive wire(s) 16 and may be formed over aportion or the entire outer surface of the reservoir 70. Electricalcontact with the skin surface may be achieved by applying force F to thebacking 12 or reservoir 76, as shown in FIG. 6B, to extrude or otherwiserelease the fluid or gel 74 from the interior of the reservoir 70 andout onto the conductive material 76 and skin as shown in FIG. 6C, wherethe openings 72 return to their closed state after the force F isremoved.

Referring to FIGS. 7A-7B, a still further embodiment of an electrodecarrier system 78 includes of an electrode assembly 79 having anelectrode body 80 which carries one or more tubular members 84 extendingfrom a lower surface thereof. The tubular members 84 projectperpendicularly away from a plane of the backing 12. In someembodiments, the electrode body 80 will be formed at least partiallyfrom a conductive material, such as a rigid or flexible metal, and/or aconductive polymer, such as a conductive silicone. In other embodiments,the electrode body 80 will be formed at least partly from anon-conductive flexible material, e.g., silicone, polyurethane, rubber,etc., which may be coated or layered with a conductive material suchthat at least the tubular members 84 are electrically conductive whileretaining their flexibility. Because of the conductivity, the electrodebody 80 and tubular members 84 may be electrically coupled directly tothe conductive wires or ribbons.

In both cases, the electrode body 80 may be secured to the backing 12such that the tubular members 84 extend through an opening in thebacking so that they can contact the patient's scalp when the backing isplaced over the head, e.g. as shown in FIG. 1. An electricallyconductive fluid or gel 88 is contained in an interior reservoir 86 ofthe electrode body 80 and can be delivered through passages in thetubular members by pressing on a flexible top of the electrode body asindicated by the arrow in FIG. 7B.

The tubular members 84 may be arranged in a uniform or an arbitrarypattern and are in a generally circular pattern as illustrated in FIGS.7A and 7B. After the backing 12 has been secured to the patient, thereservoir 86 may be pressed or urged such that the fluid or gel 88contained within is expelled through central passages along the lengthsof each of the tubular members 84 and into contact against theunderlying skin surface through corresponding distal openings. Themembers 84 will typically be elongated, e.g., having a length in therange from 1-2 cm, and may to pass readily through the patient's hair,if present, and into direct contact against the skin surface. Moreover,even with the tubular members 84 in a collapsed or deformedconfiguration, e.g. when the patient lays their head down, the tubularmembers 84 and body 80 may continue to conduct the electrical signalsfrom the underlying skin surface.

Referring now to FIG. 8, a still further embodiment of an electrodecarrier system 89 includes a tubular body 90 which may define one ormore openings 96 over its surface. The tubular body 90 may have one ormore tubular members 92 which extend in a spiral or helical pattern awayfrom the backing 12. The one or more tubular members 92 may each definea lumen therethrough which extends from a bottom of the tubular body 90and to a distal opening 94 at its tip. The backing 12 may further definea reservoir 100 which contains a volume of conductive fluid or gel 102such that the body 90 is in fluid communication with the reservoir 100.Opposed walls 104A, 104B may enclose the reservoir, and one or both ofthe walls 104A, 104B may be squeezed or otherwise translatably movedtoward the tubular body 90. Alternatively or additionally, the body 90may be rotatably secured to the backing 12 such that the body 90 andmembers 92 may be rotated about its longitudinal axis as indicated by 98to distribute the conductive fluid or gel 102 and exfoliate the skin topromote electrical contact between the electrically conductive tubularmembers 92 and the scalp.

Additionally and/or alternatively, the distal tips 94 of the members 92may present a roughened surface for contacting the skin. The optionallyroughened tips may be rotated upon the skin surface by the user to atleast partially exfoliate the skin surface to facilitate electricalcontact.

When in use, once the backing 12 has been secured to the patient's head,the tubular body 90 may be rotated manually by the user such that themembers 92 are advanced into and through any hair which may be presentupon the patient's scalp. Once the openings 94 of the distal tip arepositioned in contact with or proximity to the skin surface, one or bothwalls 104A, 104B may be actuated, e.g., squeezed by the user, such thatthe conductive fluid or gel 102 is introduced within the interior of thetubular body 90 via the openings 96. The conductive fluid or gel 102 mayflow into the tubular body 90 and within the members 92 and out throughthe openings 94 and into contact upon the skin surface.

As described above, the tubular body 90 and/or members 92 may befabricated from a conductive material which is also flexible, e.g.,conductive silicone, and/or from a flexible material, e.g., silicone,polyurethane, rubber, etc., which may be coated or layered with aconductive material such that the underlying tubular body 90 and/ormembers 92 retain their flexibility. Because of the conductivity, thetubular body 90 may be electrically coupled directly to the conductivewires or ribbons. Furthermore, with the tubular body 90 and/or members92 having an optionally flexible configuration, the members 92 maycollapse upon themselves while retaining electrical conductivity withthe underlying skin surface.

Turning now to other aspects of the present invention, the electrodecarrier system may also be utilized for other applications such aspatient motion tracking employing either visual motion tracking oraccelerometers.

In further embodiments, the electrode carrier system may be configuredas a headband, as illustrated in FIG. 9, and fitted upon a patient P.The electrode carrier system is in electrical communication with acontroller and/or output device 112 via conductive wires 114. In othervariations, the device 112 may be coupled wirelessly as well. Theelectrode assemblies 14 may incorporate any of the electrode assemblyvariations described herein and in any number of combinations, if sodesired. In the embodiment illustrated in FIG. 9, the headband backing12 may further incorporate one or more fiducial markers 110A, 110B whichallow for the visual tracking of these markers 110A, 110B within thefield of view of a camera or other optical imager 116. The markers 110A,110B may include any variety of visual indicators shown in thisvariation as high-contrast printed patterns having specified shapes, asshown. In other variations, the fiducial markers 110A, 110B may includelights such as an arrangement of LEDs.

While two markers are illustrated as an example, additional markers maybe further distributed around the circumference of the backing 12 toallow for more precise tracking, e.g., to allow for tracking when thepatient's head H may be turned in a manner which obscures one of themarkers. As noted, a camera or other optical imager 116, such as adigital camera, may be positioned in proximity to the patient P duringuse of the electrode carrier system 10 such that the electrode carriersystem 10 and markers 110A, 110B remain in the field of view 118 of theimager 116. While a single imager 116 is shown in this example,additional imagers positioned at different locations may also be used incombination to help ensure that the electrode carrier system 10 andmarkers 110A, 110B remain in the field of view 118 at all times.Additionally, the imager 116 may be optionally motorized with pan andtilt capabilities to ensure that the patient P remains in the field ofview 118 of the imager 116.

With the electrode carrier system 10 electrically coupled to thecontroller and/or output device 112, the imager 116 may also beconnected to the controller and/or output device 112 by wires or anothercommunications link 120 or to a second controller and/or output devicethrough wired or wireless communication. In this manner, the controller120 may be further programmed with a computer vision algorithm toidentify a position and orientation of the patient's head H so that thecontroller may receive the marker information from imager 116 todetermine patient movement in real time. This information can then beused for artifact rejection and diagnostic purposes. For instance,visual tracking of the markers 110A, 110B may be used to determine orconfirm whether the patient P is experiencing a convulsive seizureparticularly if the patient's detected brain signals are sonified.

In yet another variation, instead of visual markers, the electrodecarrier system 10 may incorporate one or more accelerometers 130attached within or along the backing 12, as shown in FIG. 10. The one ormore accelerometers 130 may comprise three-axis accelerometer deviceswhich are sensitive enough to detect the movement of the patient's head.This data can be transmitted to the controller and/or output device 132via conductive wires 134 for processing to determine the patient'smovements as well as motion artifact rejection. If the detectedacceleration exceeds a predetermined threshold, this may be an indicatorto the controller that these motion artifacts may be excluded fromconsideration to prevent the inclusion of artifact noise from otherdetected data.

The electrode carrier system 10 may be utilized with any combination ofelectrodes described herein and may also be used in any combination witheither the optical motion detection or accelerometer monitoring. Inother variations, both the optical motion detection and accelerometermonitoring may be utilized in combination together, if so desired.

Referring now to FIG. 11, an electrode carrier system 200 constructed inaccordance with the principles of the present invention includes anelongated backing 204, typically in the form of a headband or otherheadgear, having a plurality of electrode assemblies 202 distributedalong a length thereof. The elongated backing 204 will typically haveoverlapping ends 206 which may be adjustably attached when the elongatedbacking is placed over a patient's head, generally as shown in FIG. 1above. The overlapping ends may be attached using any conventionalmethod, such as with Velcro® hook and loop fasteners.

The electrode assemblies 202 are preferably rotatably mounted so that auser can manually rotate them back and forth as shown by arrows 208 sothat the patient's skin can be gently abraded after the elongatedbacking has been placed over the scalp. In particular, it will bedesirable to perform such manual abrasions immediately prior todispensing the electrically conductive fluid or gel as will be describedin more detail here and below. In other instances, the abrasion can beperformed while dispensing the electrically conductive fluid or geland/or after dispensing the electrically conductive fluid or gel.

Referring now to FIGS. 12-16, the electrode assemblies 202 willtypically include a lower body portion or base 210, an upper bodyportion or cap 212, and one or more tubular members 214 dependingdownwardly from a bottom surface 244 of the lower body portion. Aplunger 216 is configured to enter a chamber 224 within the upper bodyportion 212 through an opening 222. A sealed dispensing container, suchas a cartridge or sealed dispensing container 220 holds the electricallyconductive fluid or gel and is configured to be constrained within thechamber 224 while the plunger 216 extends readily outwardly from theupper body portion 212, i.e. is in its non-depressed configuration.

Once the sealed dispensing container 220 is placed in the chamber 224,the plunger 216 can be positioned so that a leading edge 228 is adjacentone side of the sealed dispensing container. By pressing the plunger 216in the direction of arrow 217, the electrically conductive fluid or gelwithin the sealed dispensing container 220 will be pressurized causing aportion of the container to pass through the dispensing hole 226. Asadditional pressure is applied with the plunger 216 the portion of thechamber within the dispensing hole 226 will rupture and cause theelectrically conductive fluid or gel to flow into a vertical passage 232within the upper body portion 212, as in FIGS. 14 and 16. Theelectrically conductive fluid or gel will then come in contact with theelectrically conductive terminal 218, and the electrically conductivefluid or gel will continue to flow through a horizontal passage 234 andon to vertical lumens 238 within the prongs 214, as seen in FIGS. 15 and16.

After flowing through the vertical lumen 238, the liquid or gel willflow outwardly through channel 240 formed in the bottom of the prong 214so that it may flow on to patient tissue in contact with the lowersurface 240 of the prong. For completeness, it is noted that the lowerbody portion or base 210 has a hollow interior 242 which is an artifactof manufacturing and which does not play a direct role in fluid flowwithin the device.

Once the entire flow path from the vertical passage 232 through thechannel 238 in the lower surface of the prong 214 is filled withelectrically conductive fluid or gel, it will be appreciated thatbiological electrical current present in the region of the liquid or gelwill be conducted to the electrically conductive terminal 218 which inturn is connected to a wire or other conductor 230 present in thebacking 204 of the electrical carrier system 200. For completeness, itis noted that the attachment of the wire 230 or other conductor to theelectrically conductive terminal 218 will be made in such a fashion thatit can accommodate rotation of the electrode assembly relative to theelongated backing 204, as shown by arrow 208 and FIG. 11.

Referring now to FIGS. 17-27, a variety of different configurations forthe lower body portions of the electrode assemblies of the presentinvention will be described. FIGS. 17 and 18 illustrate the lower bodyportion 210 which has been shown in connection with FIGS. 12-16 above.The detailed views of FIGS. 17 and 18 show that a pair of prongs 214 areformed on the lower surface 244 of the lower body portion 210. As bestseen in FIG. 18, the prongs 214 have generally crescent or arcuateshapes with curved channels formed on their lower surfaces 240. Thecurves or arcs of the prongs 214 are not, however, concentric with thecircular periphery of the lower body portion 210. Instead, the arcs ofthe prongs 214 are non-concentrically positioned on the bottom 244 ofthe lower body portion 210. In this way, gel which enters from thevertical lumens 236 of the prongs will be dispensed from the tissue sothat it will be distributed by the lower surfaces 240 of the prongs asthe electrode assembly 202 is rotated back and forth as discussedpreviously. Thus, this asymmetry of the prongs will help promotedistribution of the electrically conductive fluid or gel as it isdispensed through the vertical lumens 236 and arcuate channels 238.

In an alternative embodiment, a lower body portion or base 260, asillustrated in FIGS. 19 and 20, has three prongs 262 which areconcentrically and evenly distributed about the bottom 268. Thus,electrically conductive fluid gel which is delivered through verticallumens 264 and distributed through channels 266 formed in the lowersurfaces 270 of each prong will not be further distributed by passage ofthe lower surfaces over the gels. The presence of three prongs, however,will further promote reliable electrical connection.

Referring now to FIG. 21, an additional embodiment of a lower bodyportion 280 includes two symmetric prongs 286 having single flush ports282 in the lower surfaces 284 thereof. However a similar lower bodyportion 290 having three prongs 296 come each with a lower surface 294having a flush port 98 therein further includes the plurality of surfacefeatures 292, typically in the form of small bumps, which helpdistribute the electrically conductive fluid or gel which is beingdistributed through the ports 298.

A further embodiment of a lower body portion or base 300 having threesymmetric prongs 306 is illustrated. Each prong 306 has a lower surface304 with a plurality of surface features 302 formed thereon. The prongs,as with prior embodiments, each have vertical lumens 308 opening tochannels 310 formed in the lower surfaces for delivering anddistributing electrically conductive fluids or gels.

Still further alternative embodiments of bottom portions of theelectrode assemblies of the present invention are shown in FIGS. 24through 27. Instead of having a single lower surface on each prong witha channel of port form therein, these lower body portions have lowersurfaces with a recess for delivering the electrically conductive fluidor gel. As shown in FIG. 24, a bottom portion 320 includes threesymmetrically placed prongs 322 extending from the bottom thereof.Prongs each have lower surfaces 224, but the fluid or gel delivery ports328 are formed in recessed surfaces of the prongs.

FIG. 25 shows a similar bottom portion 340 having three asymmetricprongs 342 where the lower surfaces 344 of each prong comprise aplurality of surface features 342.

An alternative lower body portion 360, as illustrated in FIG. 26,comprises prongs 362 having adjacent gel or fluid delivery tubes 364with ports 366 therein. The prongs 362 have generally flat lowersurfaces free from surface features.

In FIG. 27, a lower body portion 380, similar to lower body portion 360,includes three prongs 386 having adjacent fluid delivery tubes. Thelower surfaces 384 of each prong 386 include surface features 382.

Referring now to FIGS. 28A-28C, an electrode assembly 400 comprises anupper portion or cap 402 and a lower portion or base 404. A plunger 406is reciprocatably received through a wall of the cap 402 and extendsinto a reservoir 412, generally as described for previous embodiments.In contrast to previous embodiments, however, the lower portion or base404 of the electrode assembly 400 has a flat bottom surface 408, as bestseen in FIGS. 28B and 28C. The electrode assembly 400, which is freefrom tubular and other protruding elements on the bottom surface of itslower portion, is particularly useful for engagement against tissuesurfaces which are free from hair, such as a patient's forehead. It willbe appreciated, as described above, that the tubular members of thepresent invention are particularly intended to allow electrical contactto be made through a patient's hair present on a scalp. As a headband,for example headband 206 in FIG. 11, circumscribes the patient's skull,at least some of the electrode assemblies 202 will be engaged againstthe patient's forehead where there is little or no hair. In suchinstances, those electrode assemblies which engage the forehead can bemade without tubular members as illustrated in FIGS. 28A-28C.

As with previous embodiments, the reservoir 412 of the electrodeassembly 400 may have a capsule or other sealed container holding theelectrically conductive gel or other fluid therein. Alternatively, thegel may be unconstrained within the reservoir 412, e.g. being introducedinto the reservoir by injection through a passage 422 having a port 424in the plunger 406. As the plunger 406 is depressed, pressure on the gelwithin reservoir 412 (either encapsulated or unconstrained) will causethe gel to flow downwardly through vertical passage 414 and out througha bottom port 416 into a slot 410 formed in the bottom surface 408. Thegel or other electrically conductive fluid will be able to distributewithin the slot and form an electrically conductive path with anelectrically conductive terminal 420 which passes through a hole 418 ina wall of the lower portion or base 404. Thus, biological electricalsignals may be coupled through the patient's skin into the electricallyconductive gel in the slot 410 so that current may pass to theelectrically conductive terminal 420. Optionally, the bottom surface 408may be modified to enhance electrical conductivity in any of the waysdescribed elsewhere herein in connection with other embodiments of theelectrode assemblies.

Referring now to FIGS. 29A-29C, an electrode assembly 430 constructed inaccordance with principles of the present invention comprises an upperportion or a cap 432 and a lower portion or base 434. Tubular members orprobes 436 project downwardly from a bottom surface of the lower portionor base 434, and a chamber 440 is formed in the lower portion or base toreceive an electrically conductive gel or other fluid through a verticalpassage 438 in the upper portion or cap 432. It will be appreciated thatthe electrode assembly 430 does not include a plunger for delivering theelectrically conductive gel as with other embodiments described herein.

The electrically conductive gel or other fluid may be injected throughthe vertical passage 438, so that the gel flows first into chamber 44and then through a vertical delivery passage 442 formed through thetubular member or probe 436. The electrically conductive gel or otherfluid will thus be able to flow onto the patient's skin so that it canform an electrically path from the skin to an electrically conductiveterminal or pin 452 which passes through the wall of the lower portionor base 434 into the chamber 440.

The electrode assembly 430 is mounted in a lower grommet 444 andoptionally in an upper grommet 446. A single grommet 444 can beconnected to a headband 445 using adhesives, staples, pins, or the likeas shown in FIG. 29B. Alternatively, the headband 445 may be sandwichedbetween the upper and lower grommets 444 and 446, as shown in FIG. 29C.In such instances, at least one of the grommets will include a slot 448to receive the electrically conductive terminal 452 and allow theelectrode assembly to be rotated within the grommets 444 and 446. Theslot allows the electrically conductive terminal 452 to move while theelectrode assembly is being rotated to enhance electrical contact to theskin, as described elsewhere herein.

In yet another embodiment, an electrode assembly 460 constructed inaccordance with the principles of the present invention comprises anupper portion or cap 462 secured to a lower portion or base 464, asillustrated in FIGS. 30A-30C. A single tubular member 466 projectsdownwardly from a bottom surface 465 of the lower portion or base 464. Avertical passage or port 468 extends from an upper or introductory port470 through the upper and lower portions in order to allow introductionof an electrically conductive gel or other fluid. A lower surface of thesingle tubular member 466 comprises a number of surface features 472,generally as described elsewhere herein, in order to allow surfacetreatment or abrasion of the tissue before, during, or afterintroduction of the electrically conductive gel or other fluid throughthe vertical passage 468.

The electrode assembly 460 can be placed in a plate or buckle 474,typically through an opening, so that a channel 467 formed between thelower surface of the upper portion or cap 462 and a flange 469 on thelower portion or base 464 receives the wall of the plate 474 to allowrotation of the electrode assembly relative to the plate. Anelectrically conductive terminal 476 passes through a wall of the lowerportion or base 464 so that it is in electrical contact with theelectrically conductive gel or other fluid which passes through thevertical passage 468 in order to form an electrically conductive pathwith the tissue contacted by the lower surface of the single tubularmember 466. The electrically conductive terminal 476 is free to movewithin a cut out region 478 on the lower surface of the buckle or plate474 as indicated by the arrows on either side of the terminal. Thebuckle 474 includes side loops or cut outs 480 which permit the buckleto be attached to a strap in order to form a headband by joining thebuckle to other similar structures.

Referring now to FIGS. 31A and 31B, a still further electrode assembly482 constructed in accordance with the principles of the presentinvention comprises an upper portion 484 and a lower portion 486. Theelectrode assembly 482 is received within a buckle or plate structure492 so that it is free to slide within a slot 494 in the direction ofthe arrow shown in FIG. 31A. The electrode assembly 482 has a port 498for receiving an electrically conductive gel or other fluid anddistributing that fluid through a lower port 488 which is located in anarray of surface features 490 on a lower surface of the lower portion486. In this way, after the electrode assembly 482 is engaged against apatient's skin, typically as part of the headband, the electrode can betranslated back and forth relative to the buckle 492 and headband inorder to treat the skin surface and enhance electrical conductivity, asdescribed in greater detail elsewhere herein. The buckle or plate 492includes slots 496 on either side in order to facilitate attachment tothe headband assembly.

The following numbered paragraphs further described the presentinvention:

31. A method for placing a plurality of electrodes on a patient's scalp,said method comprising:

placing a headband around the patient's scalp, said headband carrying aplurality of electrode assemblies;

engaging distal tip(s) of one or more tubular members extending from atleast some of the electrode assemblies against scalp tissue;

extruding a conductive fluid or gel from a reservoir disposed in atleast some of the electrode assemblies through the tubular members ofthose electrode assemblies to form an electrically conductive path tothe patient's scalp tissue; and connecting the plurality of electrodeassemblies to a controller and/or output device configured to receivelow power biological current from the electrode assemblies.

32. A method as in claim 31, wherein the distal tips of at least some ofthe tubular members are positioned through hair on the patient's scalp.

33. A method as in claim 31, further comprising moving at least some ofthe plurality of electrode assemblies to abrade scalp tissue adjacentthe distal tip(s) of said one or more tubular members in order to lowercontact resistance between the electrode assembly and the scalp tissue.

34. A method as in claim 33, the distal tips of at least some of thetubular members define a skin preparation surface.

35. A method as in claim 31, wherein the conductive fluid or gel isextruded from the reservoir through lumens in the tubular members andout of the distal opening(s) on distal tips of the tubular member(s)onto the scalp tissue.

36. A method as in claim 35, wherein the conductive fluid or gel isextruded out of groove(s) on the distal tips of the tubular member(s).

37. A method as in claim 31, wherein extruding the conductive fluid orgel from the reservoir comprises manually applying external pressure toa sealed dispensing container which holds the conductive fluid or gel,wherein the sealed dispensing container is incorporated into theelectrode assembly.

38. A method as in claim 37, wherein applying external pressure to thesealed dispensing container comprises pressing a plunger to engage arupturable sealed dispensing container that carries the conductive fluidor gel.

39. A method as in claim 37, wherein applying external pressure to thesealed dispensing container comprises manually squeezing a tube,manually depressing a syringe plunger, and rolling a squeeze tube

40. A method as in claim 31, wherein the electrically conductive path tothe patient's scalp tissue is formed solely by the conductive fluid orgel.

41. A method as in claim 31, wherein the electrically conductive path tothe patient's scalp tissue is formed at least partly by the electricallyconductive structure on the tubular members.

42. A patient monitoring system, comprising:

one or more electrodes configured for contacting a skin surface;

a backing which is securable to a patient body and is further configuredto maintain the one or more electrodes against the skin surface;

at least one motion detection apparatus attached to the backing; and

a controller for receiving electrical data from the one or moreelectrodes and motion data related to the at least one motion detectionapparatus, wherein the controller is programmed to process theelectrical data and motion data.

43. The system of claim 42 wherein the one or more electrodes eachcomprise an electrode body which is at least partially electricallyconductive, one or more tubular members extending from the electrodebody, each of the one or more tubular members defining a lumentherethrough and a distal opening.

44. The system of claim 43 further comprising a reservoir having acompressible structure and containing a conductive fluid or gel which isin fluid communication with the one or more tubular members.

45. The system of claim 42 wherein the backing is configured as aheadband for placement upon a patient's head.

46. The system of claim 42 wherein the at least one motion detectionapparatus comprises one or more fiducial markers.

47. The system of claim 46 further comprising an imaging apparatusconfigured to image the one or more fiducial markers.

49. The system of claim 47 wherein the imaging apparatus comprises acamera.

50. The system of claim 46 wherein the imaging apparatus is incommunication with the controller.

51. The system of claim 42 wherein the at least one motion detectionapparatus comprises one or more accelerometers.

The applications of the devices and methods discussed above are notlimited to electrical sensing upon the patient's head but may includeany number of further treatment applications. Moreover, such devices andmethods may be applied to other treatment sites upon the body.Modification of the above-described assemblies and methods for carryingout the invention, combinations between different variations aspracticable, and variations of aspects of the invention that are obviousto those of skill in the art are intended to be within the scope of theclaims.

1. (canceled)
 2. A method of measuring electrical signals from asubject, the method comprising: positioning an electrode assemblyadjacent skin of the subject; preparing a surface of the skin of thesubject with the electrode assembly; dispensing a conductive fluid orgel to the skin with the electrode assembly; and measuring one or moreelectrical signals of the subject from the skin of the subject with theelectrical assembly.
 3. The method of claim 2, wherein positioning theelectrode assembly adjacent skin of the subject comprises positioning alower surface of a tubular member of the electrode assembly adjacent theskin of the subject.
 4. The method of claim 2, wherein the skin of thesubject comprises a scalp of the subject.
 5. The method of claim 2,wherein preparing the surface of the skin of the subject comprisesabrading the surface of the skin with a skin preparing surface of theelectrode assembly.
 6. The method of claim 5, wherein abrading thesurface of the skin comprises moving said skin preparing surface againstthe skin.
 7. The method of claim 6, wherein moving said skin preparingsurface against the skin comprises one or more of rotating ortranslating said skin preparing surface.
 8. The method of claim 5,wherein the skin preparing surface is a lower surface of the electrodeassembly.
 9. The method of claim 5, wherein the skin preparation surfaceis non-concentrically oriented on the electrode assembly.
 10. The methodof claim 5, wherein the skin preparation surface comprises at least oneof (a) an abrasive and (b) surface features on a distal tip of theelectrode assembly.
 11. The method of claim 2, wherein the conductivefluid or gel is dispensed from a reservoir of the electrode assembly.12. The method of claim 11, wherein the reservoir comprises a sealeddispensing container which is constrained within a chamber in theelectrode body.
 13. The method of claim 2, wherein dispensing theconductive fluid or gel comprises depressing a plunger coupled to thereservoir of the electrode assembly.
 14. The method of claim 2, whereindispensing the conductive fluid or gel to the prepared skin creates aconductive path with the conductive fluid or gel from the skin of thesubject to an electrically conductive terminal of the electrodeassembly.
 15. The method of claim 2, further comprising positioning aplurality of the electrode assemblies adjacent the skin of the subject.16. The method of claim 15, wherein positioning the plurality of theelectrode assemblies adjacent the skin of the subject comprises placinga backing for the plurality of the electrode assemblies adjacent theskin of the subject.
 17. The method of claim 15, wherein the backingcomprises a headband, and wherein placing the backing adjacent the skinof the subject comprises placing the headband at least partially arounda head of the subject.
 18. The method of claim 2, wherein measuring oneor more electrical signals comprises measuring an EEG signal of thesubject.
 19. The method of claim 2, further comprising recording themeasured one or more electrical signals of the subject.
 20. The methodof claim 2, further comprising transmitting the measured one or moreelectrical signals of the subject to one or more of a controller or anoutput device.
 21. The method of claim 2, further comprisingtransmitting the measured one or more electrical signals of the subjectto a remote computing device.